1. Field of the Invention
The invention relates to an optical disk drive, and more particularly, to a holder for disk drives having an improved chuck structure for seating a disk.
2. Description of the Related Art
Optical disk drives, in particular, slim optical disk drives include a CD-ROM drive, a DVD-ROM drive, a CD R/W drive and so on. Such an optical disk drive receives a disk to write or read records into/from the disk while turning the disk. A slim optical disk drive is particularly mounted on a slim computer such as a notebook computer.
The slim optical disk drive is limited in height. That is, since the slim optical disk drive is mounted on a thin main body, the height of the disk drive itself is limited. Therefore, the slim optical disk drive requires a holder structure for grasping a disk unlike a disk drive mounted on a typical desktop computer.
FIG. 1 shows a conventional holder structure. As shown in FIG. 1, the conventional holder for disk drives comprises a flat cylindrical hub 103 sized equal to a central opening of a disk for being inserted into the central opening of disk and chucks 101 for elastically projecting from lateral regions of the hub 103 under the force of springs 102. The holder is placed in a central portion of a circular base 110, and a lower base 140 is provided with a stator assembly and a rotor assembly.
A rubber turntable 130 is provided around the holder for wrapping the holder therein so that the disk is seated or mounted on the turntable 130. The rotor and stator assemblies in the lower base 140 of the holder cooperate to turn the turntable 130 and the holder, and thus the disk grasped by the holder along with the turntable 130. As the disk is turned, writing or reading means write or read desired data into/from the disk while moving in a radial direction of the disk.
Each of the chucks 101 used in the conventional holder grasps a disk according to a process shown in FIG. 2. FIG. 2(a) illustrates that the disk 100 contacts an upper portion of one of the chucks 101. As the user further moves the disk 100 downward, the chuck 101 is pushed backward slowly. As the disk 100 is further moved downward, the chuck 101 is pushed to the innermost position thereof in the holder hub 103 as shown in FIG. 2(b). When the disk 100 is completely seated on the turntable, the chuck 101 projects again toward the disk as shown in FIG. 2(c).
The chuck 101 has upper and lower faces, which taper at predetermined inclinations, and a peak portion at leading edges of the upper and lower faces. The chuck 101 functions to press the disk under a predetermined amount of force so that the disk may not slip upward out of the turntable while it is turning.
The disk holder structure using the above chucks has the following drawbacks. First, the central chucks are moved only in a horizontal direction, thereby enhancing seating force, i.e., force for seating the disk. The enhanced seating force causes inconvenience to the user in using the disk drive, and thus the user applies excessive force to the disk holder thereby potentially damaging the disk drive and even the main body.
If the tension of the springs which are mounted on rear of the chucks is adjusted to decrease the seating force, restraining force against separation or simply restraining force, i.e., force required for separating the disk or resisting against separation of the disk will be also reduced. Then, the disk may be separated even under slight impact during high speed rotation so that the disk drive may not properly perform its function. Therefore, the art requires a novel holder structure which can maintain sufficient amount of restraining force against separation while decreasing seating force.
As shown in FIG. 1, the peak of the chuck 101 has a semicircular configuration on a horizontal plane. In this configuration, the peak of the chuck 101 performs point-to-point contact with the periphery of the central opening of the disk, which does not increase the restraining force against separation of the disk. Further, in the case of a DVD for example having a double layer structure, an intermediate groove of the double layer structure may trap the chuck (i.e., half chucking) potentially causing problems to the seating process of the disk.
Therefore, the art also requires a structure capable of preventing half chucking in which the chuck is trapped by an intermediate portion of the disk while increasing the restraining force against separation.